fix: Allow to remove the finalizer even if the ScaledObject isn't valid

BUILD.md

@@ -287,7 +287,8 @@ Follow these instructions if you want to debug the KEDA webhook using VS Code.
      clientConfig:
        url: "https://${YOUR_URL}/validate-keda-sh-v1alpha1-scaledobject"
    ```
-   **Note:** You could need to define also the key `caBundle` with the CA bundle encoded in base64 if the cluster can get it during the manifest apply (this happens with localtunnel for instance)
+   **Note:** You need to define also the key `caBundle` with the CA bundle encoded in base64. This `caBundle` is the pem file from the CA used to sign the certificate. Remember to disable the `caBundle` inyection to avoid unintended rewrites of your `caBundle` (by KEDA operator or by any other 3rd party)
+
 
 4. Deploy CRDs and KEDA into `keda` namespace
    ```bash

CHANGELOG.md

@@ -54,6 +54,7 @@ To learn more about active deprecations, we recommend checking [GitHub Discussio
 
 ### Fixes
 
+- **General**: Allow to remove the finalizer even if the ScaledObject isn't valid ([#4396](https://github.com/kedacore/keda/issue/4396))
 - **AWS SQS Scaler**: Respect `scaleOnInFlight` value ([#4276](https://github.com/kedacore/keda/issue/4276))
 
 ### Deprecations

apis/keda/v1alpha1/scaledobject_webhook.go

@@ -65,13 +65,30 @@ func (so *ScaledObject) ValidateCreate() error {
 func (so *ScaledObject) ValidateUpdate(old runtime.Object) error {
 	val, _ := json.MarshalIndent(so, "", "  ")
 	scaledobjectlog.V(1).Info(fmt.Sprintf("validating scaledobject update for %s", string(val)))
+
+	if isRemovingFinalizer(so, old) {
+		scaledobjectlog.V(1).Info("finalizer removal, skipping validation")
+		return nil
+	}
+
 	return validateWorkload(so, "update")
 }
 
 func (so *ScaledObject) ValidateDelete() error {
 	return nil
 }
 
+func isRemovingFinalizer(so *ScaledObject, old runtime.Object) bool {
+	oldSo := old.(*ScaledObject)
+
+	soSpec, _ := json.MarshalIndent(so.Spec, "", "  ")
+	oldSoSpec, _ := json.MarshalIndent(oldSo.Spec, "", "  ")
+	soSpecString := string(soSpec)
+	oldSoSpecString := string(oldSoSpec)
+
+	return len(so.ObjectMeta.Finalizers) == 0 && len(oldSo.ObjectMeta.Finalizers) == 1 && soSpecString == oldSoSpecString
+}
+
 func validateWorkload(so *ScaledObject, action string) error {
 	prommetrics.RecordScaledObjectValidatingTotal(so.Namespace, action)
 	err := verifyCPUMemoryScalers(so, action)

apis/keda/v1alpha1/scaledobject_webhook_test.go

@@ -449,6 +449,32 @@ var _ = It("should validate so creation when min replicas is > 0 with only cpu s
 
 })
 
+var _ = It("should validate the so update if it's removing the finalizer even if it's invalid", func() {
+
+	namespaceName := "removing-finalizers"
+	namespace := createNamespace(namespaceName)
+	workload := createDeployment(namespaceName, true, true)
+	so := createScaledObject(soName, namespaceName, workloadName, "apps/v1", "Deployment", true)
+	so.ObjectMeta.Finalizers = append(so.ObjectMeta.Finalizers, "finalizer")
+
+	err := k8sClient.Create(context.Background(), namespace)
+	Expect(err).ToNot(HaveOccurred())
+
+	err = k8sClient.Create(context.Background(), workload)
+	Expect(err).ToNot(HaveOccurred())
+
+	err = k8sClient.Create(context.Background(), so)
+	Expect(err).ToNot(HaveOccurred())
+
+	workload.Spec.Template.Spec.Containers[0].Resources.Requests = nil
+	err = k8sClient.Update(context.Background(), workload)
+	Expect(err).ToNot(HaveOccurred())
+
+	so.ObjectMeta.Finalizers = []string{}
+	err = k8sClient.Update(context.Background(), so)
+	Expect(err).ToNot(HaveOccurred())
+})
+
 var _ = AfterSuite(func() {
 	cancel()
 	By("tearing down the test environment")